Master Corporal Tiernay was deployed with 1st Battalion, The Royal Canadian Regiment Battle Group, in Afghanistan. While conducting a forward combat patrol on October 14, 2006, the battle group commander’s tactical headquarters came under intense enemy fire, immobilizing their vehicle. Master Corporal Tiernay dismounted the vehicle to assist in securing the area. Unfortunately, attacks by the enemy claimed the lives of two soldiers. His courageous actions prevented further casualties and brought great credit to the Canadian Forces and to Canada.